a) Field of the Invention
The invention is directed to a laser scanning microscope comprising a laser unit, scanning means, a microscope stand, a detection unit and a control/receiving unit, wherein the spectral characteristics of the detection unit can be freely programmed by a switching mirror array integrated in a monochromator. The switching mirror array (one- or two-dimensional) can be constructed, for example, as a DMD (Digital Mirror Device or switchable-mirror arrangement). The laser scanning microscope according to the invention enables different operating modes. On the one hand, the emitted spectrum can be detected with high resolution on every scanned pixel (in the specimen); on the other hand, the emitted spectrum can be divided into a quantity of spectral portions (zones on the switching mirror array) and each of these portions can be treated as a separate electronic detection channel (which is advantageous, e.g., for receiving multiple fluorescences). Further, a freely programmable confocal diaphragm (pinhole) can be realized by means of an additional switching mirror array which is introduced in a conjugate plane to the object plane.
b) Description of the Related Art
Modern laser scanning microscopes for examination of (fluorescing) specimens generally comprise a detection unit which divides the (fluorescent) radiation emitted from the specimen into a certain quantity of (generally up to 4) detection channels by means of dichroic splitter layers and filter layers (principle of optical multichannel analyzer—OMA). These splitters/filters are generally held in rotatable revolving wheels or linear-displaceable disks. In this way, a spectral adaptation of the channels to the spectral characteristics of the specimen radiation is possible up to a certain degree. However, since only a finite number of dielectric splitters and filters can be received in every holder and the spectral characteristics of every individual splitter/filter are determined in the process of their manufacture, this arrangement is not flexible enough to be adapted to the specimen spectrum in an optimum manner in many cases of application (FIG. 1).
A confocal microscope with DMD mirror arrays for illumination and/or detection is described in U.S. Pat. No. 5,587,832.